Resolved questions
How do you know what's natural in Korean and what's not?

that's one of the hardest struggles for a lot of people when learning an East Asian Language, especially as a westerner. My general advice you have to copy and learn from Native speakers, and you have to realize a lot of things that people say in the west don't equal to korean. for example, in Korean they don't use the words "excited to do...." and " should" like westerners do. In korean you woudn't say I am so excited go there for example, you would say " I expect to go there.." or in korean they don't say " we should do this..." instead just simply " let's do...." So i think by imitating from speakers and being aware that many things don't translate the same way in Korean as the west you will get a sense of what is natural in Korean